Furnace fireplace



July 9, 1963 H. c. HOWREY FURNACE FIREPLACE 2 Sheets-Sheet 1 Filed Feb.24. 1960 2 A: g T

A 8 B l w 9 37 INVENTOR. HAROLD C. HOWREY BYWM ATTORNEY July 9, 1963 H.c. HOWREY 3,09

FURNACE FIREPLACE Filed Feb. 24, 1960 2 Sheets-Sheet 2 INVENTOR. HAROLDC. HOWREY NW6 W ATTORNEY This invention relates generally to heatingapparatus adapted to heat a single room or plurality of rooms in abuilding and more particularly to a prefabricated fireplace soconstructed as to heat by radiation and convection and capable ofutilizing either solid or liquid fuel. The

application is a continuation in part of application Serial Number606,109 filed August 24, 1956, now abandoned.

Fireplaces in common use are usually constructed to operateindependently of the heating equipment provided to maintain the rooms orbuildings at comfortable temperatures. Generally, such fireplaces relyon radiation from the flame and walls to heat the rooms in which theyare disposed. The resulting heat is intense immediately in front of thefireplace and falls rapidly away with distance so that at six or eightfeet in front or to the sides of the fireplace very little warmth isobtained. Another disadvantage of the common fireplace is the lack ofprovision of adequate temperature regulating means so that the fuel bumseither too fast or too slow. The damper when provided must be manuallyregulated, is frequently inaccessible for manual operation during thetime a fire is burning, and permits inefficient loss of heat through theflue even when partially closed by reason of the smallness of theexhaust area it controls with consequent rapid draft and fast burningflame. Unless a second supply of fuel, wood or charcoal is maintained atall times, the fireplace cannot be operated since it cannot burn theprimary heating fuel, oil. Because of these disadvantages, the averagefireplace is more ornamental than utilitarian and in fact many owners,for these reasons, maintain a simulated fire in the fireplace and thusconvert it to an entirely ornamental function.

The principal object of this invention is to construct a fireplace whichwill avoid the disadvantages enumerated above. This is accomplished bythe provision of a fireplace which burns either solid or liquid fuel,which heats by convection as well as by radiation, which is equippedwith thermostatically controlled regulating means, and which may beinstall-ed as a furnace to heat a plurality of rooms or an entirebuilding.

Another object of the invention is to provide a combina ti-on fireplaceand furnace with an enlarged damper and enlarged firebox exhaustpass-age into the chimney, which will reduce the velocity of thecombustion products and allow a slower burning fire with consequentreduction of heat loss.

A further object of the invention is to structurally combine a fireplaceand furnace in a prefabricated unit capable of use with air ducts in abuilding to provide a hot air circulating system capable of maintainingthe entire building heated to a regulated temperature.

A still further object of the invention is to provide within acombination fireplace and furnace capable of burning solid and liquidfuel, a thermostatic unit having separate elements for regulation of theliquid and solid fuel fires and each being manually preset to maintain aselected temperature range.

Still another object of the invention is to provide in a liquid burningfireplace the means for properly feeding the liquid fuel, maintaining aproper and varying level of the liquid in the burner in accordance withvariations in damper positions together with provisions for cutting offthe supply of liquid when temperature or safety con- 3,096,754 PatentedJuly 9, 1963 ditions so require including such times as a solid fuel issubstituted;

The novel features that are considered characteristic of the inventionare set forth with particularity in the appended claims. The inventionitself, however, both as to its organization and its method ofoperation, together with additional objects and advantages thereof, willbest be understood from the following description of a specificembodiment when read in connection with the accompanying drawingswherein like reference characters indicate like parts through theseveral figures and in which:

FIGURE 1 is a perspective view of a prefabricated fireplace and furnacecombination constructed in accordance with the invention, partiallybroken away for convenience of illustration;

FIGURE 2 is a reduced scale section taken along line 22 of FIGURE 1 andadding portions of a building to show the fireplace and furnacecombination installed therein;

FIGURE 3 is a vertical central section taken along line 33 of FIGURE 1and showing the oil burner;

FIGURE 4 is a fragmentary perspective view of the oil burner, lookingtoward its right end as removed from FIGURE 1 and showing the oil shutoff control associated therewith;

FIGURE 4A is a fragmentary vertical section, taken midway the width ofthe fireplace and illustrating the central, upper air passages;

FIGURE 5 is a diagram in perspective of the damper, and thermostatcontrol and oil regulator unit corresponding to FIGURE 1 but omittingstructural features of the fireplace, furnace combination;

FIGURE 6 is a sectional view of the oil regulator unit taken verticallyfrom front to rear thereof and toan en larged scale;

FIGURE 7 is an enlarged vertical section of the safety shut off valve ofthe oil burner;

FIGURE 8 is a side view of the thermostat control unit shown partiallyin vertical section;

FIGURE '9 is a section taken on line 9-9 of FIGURE 8, with parts brokenaway for convenience of illustration;

FIGURE 10 is an end sectional view of the oil burner control section ofthe thermostat unit, taken on line 1010 of FIGURE 8, parts being brokenaway to better illustrate internal features;

FIGURE 11 is an end sectional view, taken on line 1111 of FIGURE 8,looking in the direction of the arrows toward the hard fuel thermostatcontrol housing and spring, with parts broken away, and

FIGURE 12 is an enlarged fragmentary section taken on line 1212 ofFIGURE 9.

The illustrated combination fireplace and furnace comprises an outerbox-like chamber or shell S. The shell S has side or end walls 2, a rearwall 3, a bottom wall 4, and a top wall 5. A fine opening 8 for passageof combustion products and a duct 9, comprising a warm air outlet, forpassage of hot air open through the top wall 5. The bottom of the shellhas an opening 10 through which air is introduced by way of an air duct11. An auxiliary fresh air intake 39 is provided through the end wall 2of the shell S and is opened and closed by the gate 40 in a manner to belater described. This air intake may lead from any suitable location, asfrom the outside of the building through a duct not here shown. An ashdisposing opening 12 leads through the bottom wall 4 to an ash receivingchamber in the building wall. Ashes may be removed by opening the door38 on the exterior of the building. A trap door 35 is located in thebottom wall 14 of the firebox and communicates with the ash opening 12by way of the spout 36 which enters the ash receiving chamber or trap 37adjacent the clean out door 38. The front faceof the shell S has a largeopening 6 for passage of. radiated heat .to the .room in which thefireplace is located and a smaller opening 7 closed by a grill 34,preferably of the louver type which permits the grill-openings whoopened, closed or partially closed The opening 7 and grill 34 permitconvection currents of warmed air to passed from the combinationfireplace and furnace into the room.

A firebox F is disposed within and spaced from all of the walls ofcasing S, except the front wall. The firebox comprises a bottom wall 14,a rear wall 15, side walls 16 and a flat top 17. The front'of thefireboxcomprises an upper front partial wall or closure 18. This wall extendsupwardly and connects with. a pair of discharge passageways O, eachhaving an inclined portion 18A which extends upwardly andrearwardly intoa relatively flat portion 18B terminating in theflue nozzle 19. The fluenozzle 19 enters into the'flue stack 20.

The flue nozzle 19 has a bottom wall 27 which is fixedly secured to thetop wall.1'7 of the firebox F at 28, see FIGURE 2. This bottom wall isinclined downwardly towards the back of the chimney so as .to providespace for mortar 29 to be received to prevent moisture from getting onthe bottomwall 27uand also to prevent such water as condenses in thestack from running over into the firebox. The inclined wall 27 alsoserves to turn back downdrafts-oc-curring in flue 8 to increase theefficiency of the apparatus as will be explained more fully hereinafter.

The two discharge passageways O, O are divided by. a channel 21. Each ofthese passageways has end walls 22' and 23 converging towards andjoining the rear edge of the stack nozzle 19, as best illustrated inFIGURE 1. The passageways O, 0 form apair offireplace smoke outletswhich join the flue nozzle 19 at its front and sides. This constructionprovides a relatively large smoke receiving area at the topv of thefirebox which.

gradually tapers into the nozzle 19 and has a relatively large exhaustopening thereto. Furthermore, the converging walls 22 and 23 establish apath for the updraft of air and are instrumental in directing smokeefiiciently up the flue. rises and is separated into two columns by thechannel 21. Each column of smoke upon rising contacts the upper walls18A as well as the converging side walls 22 and 23 and is caused to rollforwardly and downwardly and turn into a spiral pattern which leadsupwardly to the flue.

Such structure reduces the velocity of the air and smoke being drawninto the stack, -and minimizes the heat loss because of the slowermoving draft without impeding the exhaust of a large volume of air,smoke and other combustion products.

Referring to FIGURES 2 and particularly, smoke control dampers D and Dare fixedly mounted on the shaft 24 which is pivotally journaled at 25transversely of the discharge passageways O. The dampers control theexhaust ports 26 between the firebox Fand the smoke outlets O. InFIGURE-2, one damper 24 is illustrated in full lines when fully closedand by dotted lines when fully opened.

The firebox F is reinforced and supported'in spaced relation to theshell S byv a plurality of bars 41 which are secured to the fireboxinany desired manner, as by welding, and which do notrestrict theexpansion and con traction movement developed within the firebox walls.The bottom wall 14.of the firebox F is supported above the bottom wall 4of the shell S, providing a space 30 completely across and under thebottom of'the firebox F. The rear wall: of the firebox'is spaced fromthe rear wall3-of' the shell providing an air space 31 completely acrossand up to the top of the said firebox. An air space 32 is formed betweenthe top wall 17 of the firebox andthe top wall 5 of the shell andextends toward both sides ofthe firebox at each side o-f'the flue nozzle19 and discharge passageways O, O, as best illustrated in FIG- Morespecificaally smoke fromburning fuel;

URE 1. Referring to FIGURE 4A, an air space 33 exists between the topwall 17 of the firebox and the bottom wall 27 of the flue nozzle 19.This space joins with the channel 21 between discharge passageways 0.These various spaces around the firebox provide passageways for air tomove in contact with the firebox walls and by convection, pass into thecirculating ducts, as will be further explained hereinafter.

A preferred form of burner B is illustrated particularly in FIGURES l,3, 4 and 5. The burner comprises an elongated boxlike unit 42 having aninner chamber 43 and an outer downwardly extending wall 44 formedintegral with but spaced from the chamber. A pair of walls 46 aresecurely afiixed to the lower portions of walls 44 by any suitablemeans, such. as the screws 47. In this manner, a pair of air inletmanifolds 45 are formed between the walls 44 and 46 which extend, alongboth sides of the burner B and have inlet passages extending below itsbottom. A series of holes 43 admit air from the manifolds 45 intothemixing chamber 49.

The mixing chamber 49'has an adjustable nozz-le N super-imposedthereabove and extending the full length of the burner. The nozzle isformed of a pair of oppositely disposed adjustable gates or grates 54)which are preferably in the form of plates and pivotally mounted on oneof their edges within the sockets 51 formed on the upper edge of theunit 42. The opposite edges 52 of gates 50 are adapted :to be movedtowards and away from one another by raising and lowering them inregards to the burner. The gates 50 have a series of spaced plates orsegments 55 formed on their adjacent faces between which air and flamesgenerated within the mixing chamber 49 can pass and exit through theelongatedopening between edges 52 of gates 50. Each plate '55extendstoward a mating plate on the opposite gate and is provided witheither a tooth 53 or a notch 54. Mating teeth and notches on oppositeplates cooperate with each other so thatupon movement of the gates 50'to open-position, the gates will be retained in such adjusted positionto provide an opening for exit of the flame.

The gates Stl may be opened or closed manual-1y by manipulationof-handles 56. The open position is shown in FIGURES 2, 3 and 4 whilethe closed position is illustrated in FIGURES 1 and 5. When the gatesare closed, solid fuel will be used within the firebox, but when thegates are opened, a liquid, preferably oil, is used for fuel.

Referring to FIGURES 3, 5 and 6, fuel oil is delivered into the base ofthe burner B by means of the supply line 57. The fuel is vaporized inthe mixing chamber 49 by heat radiated from the gates 50 land the flame.A pilot flame exists at the point 58, receiving its air for combus tionthrough the tube 59 from the air manifold 45. As long as this pilotlight is on the safety unit 69 will allow oil to enter into the mixingchamber 49.

The oil safety unit 6th comprises a relatively heavy metallic cap 61,having a hollow tubular downward extension 62 forming part thereof andadapted to slide within the tubular nipple 63, extending upwardly fromthe bottom wall 64 of the mixing chamber 49'. The cap 61 controls theflow of fuel from the supply line 57 through the port 65 within thenipple 63, through the port 66 of the extension 62. A spring-67 holdsthe cap 61 in its up position as shown in FIGURE 7 when the pilot-flame58 is off but when the pilot flame is on, heat delivered by the pilotagainst the cap 61 will reduce the tension of the spring 67 allowing theweight of the cap 61 to lower the extension 62 within nipple 63 so thatthe port 66 will register with the port 65 allowing fuel to flowtherethrough into the mixing chamber 49. In the event the pilot flamegoes out, the tension in the spring '67 will increase, raising the cap60 so as to shut off the supply of oil going to the mixing chamber whenthe ports '65- and 66 move out of registry.

The flow of oil to the burner B is also controlled bythe oil regulatingunit R. Referring to FIGURES 5 and 6, this unit comprises a floatchamber 6 8 having a float valve 69 therein which is actuated by thefloat 70. As the float 70 raises, it will close 'valve 69' and shut offthe flow of oil from the supply line 71 into the float chamber 68. Oilpasses from chamber 68 into line 57 and thence to burner B, aspreviously described.

The operation of the float valve 69 is further controlledthermostatically and also by a separate manual means. The supply of oilto the unit R and hence to burner B may be completely shut off by amaster shut off valve 72, in supply line 71. Valve 72 is actuated bymovement of the burner gates 50 through the connecting rod 73. One endof rod 73 is connected to the crank of valve 72, FIG. 6 and the otherend of rod 73 is connected to the crank 74 forming part of one of thegates 59 by way of the stub shaft 75, FIG. 4. When the gates 50 are inlowered position as shown in FIGURES l and 5, the valve 72 will beclosed shutting off the supply of fuel oil but when the gates 50 aremanually moved to the position shown in FIG- URES 3 and 4, the valve 7-2will be opened, admitting fuel oil to burner B.

The thermostatic control of regulating unit R is obtained throughregulation of damper movements. A crank 105 is fixedly secured to thetransverse shaft 24 of the dampers D and D and is adapted to operate theconnecting rod 106. The lower end of this connecting rod is pivotallyconnected at 1W7 to the walking beam 1138 which operates the plunger109. The lower end of the plunger 199 engages the float lever 11%,either forcing the said lever down or allowing it to rise, opening orclosing the float valve 6-9. When the dampers D and D move to close, theconnecting rod 106 is raised. This pivots the walking beam 198 so as tolower the plunger 109 closing down the float valve 69, which shuts offthe supply of oil into the burners B by way of the supply line 57. Whenthe dampers D and D tend to open, the connecting rod 196 is lowered,pivoting the walking beam 1128 so as to raise the plunger i199permitting the float valve 69 to open adding more fuel to the burner B.

The thermostatic control mechanism is best illustrated in FIGURES 1, 5and 8. The dampers D and D are opened and closed by the action ofthermostat unit T. The opening may vary depending upon the setting ofthe thermostat unit. In the burning of hard fuel, the damper operatesmore fully opened than does the damper while burning fuel oil,therefore, a dual operating thermostat has been provided.

Thermostat unit T includes a casing 76 adapted to be located within thefront portion of the firebox behind the front wall 18, FIGURE 2.Extending forwardly from the casing is a tubular housing 77, terminatingin a dial 78. Dial 78 is located outside the firebox on the face 79 ofthe fireplace, preferably centrally located.

Journaled within the sleeve housing 77 is a sleeve 80 which is rotatedby the lever 81, fixedly secured to its outer end. The inner end of thesleeve 80 has a crank 82 fixedly secured thereto at 33, see FIGURE 8.Connected to the crank 82 is a rod 84, which raises or lowers the gate40 by way of the connecting rod 85 through the bell crank 86, as bestshown in FIGURE 5. Thus, manual operation of lever 81 on the thermostatcontrol unit T serves to vary the opening or close the gate 40' which,when open, admits auxiliary fresh air into the circulating air chambersurrounding the firebox B.

The thermostat unit T includes a sleeve 87 journaled within the sleeve81 A knob 88 is fixedly secured to the outer end of sleeve 87 and bevelgear 89 is fixedly connected by any suitable means to the inner end ofsleeve 87. The bevel gear 89 also forms part of the drum or housing 90.Extending outwardly from the drum 90 is a cam flange 91 having an offsetportion 92 formed thereon. A thermostat spring 93, preferably ofbimetal, has one of its ends secured to the drum 91) at 94. The otherend of the spring 93 is secured at 97 to the hub 95 of lever 96. Lever9-6 and its hub 95 rotate freely on the tubular shaft 98, which isjournaled within the tubular shaft 87. Shaft 98 is fixedly secured tothe manipulating knob 125.

A second drum 99 is fixedly secured to the end of shaft 98. Within thisdrum is a second thermostatic spring 100. One end of spring 160 issecured to the drum '99 while the other end is secured to shaft 101which floats within the tubular shaft 98. A crank 102 is fixedly securedto shaft 101 and is connected to the dampers D and D by way of theconnecting rod 103:. The outside face of drum 99 has a fixed stop 104for arresting movement of lever 96. The drum is held in a manuallyselected position by the spring loaded 'ball 111, FIGURE 12, whichregisters with the depressions 112 formed within the flange 91. The ball111 operates within a plunger 113 which is slidably mounted within thebase 114 afiixed to the casing 76. A roller 115 is journaled to the arm116 forming part of the plunger 113. This roller engages the cam flange91 of the drum 99, pushing the same against the said spring loaded ball111. When drum 90 is rotated to a position in which the oflset flangeportion 92 is opposite roller 115, the plunger 113 together with roller115 and the spring loaded balls 111 and 123 will slide together in thebase 114- and cause the ball 123 to engage one of the lockingdepressions 124 on drum 99.

The operation of the thermostat unit T, when the fireplace is using fueloil, is rescribed as follows, particular reference being made to FIGURES8 and 10 illustrating the thermostat unit parts as manually set forconsumption of such fuel. The knob 88 is set by hand so that a certainpredetermined tension, depending upon desired temperature range, isplaced on the thermostat spring 93, the knob being turned clockwise.This turns sleeve 87, drum 90 and spring 93 clockwise, as viewed in FIG-URES 5 and 8, or counterclockwise in FIGURE 10. The lever 96 connectedto one end of spring 93 is also moved in a counterclockwise direction,as viewed in FIG- URE 10, causing the said lever to bear against thestop 104 of the drum 99 and move said drum clockwise, as viewed inFIGURE 11. This places a tension on the thermostatic spring whichrotates the floating shaft 101 clockwise, as viewed in FIGURE 5, raisingthe dampers D and D in the direction of the arrow, or to the positionshown by dotted lines in FIGURE 2. The amount of clockwise rotation ofthe knob 88 will govern the amount that the dampers are opened.

As the springs 93 and 100 are heated 'by combustion products of theburning oil, they will expand, causing the shaft 101 to turncounterclockwise, lowering the connecting rod 103 and the dampers towardthe closing position of the said dampers. This reduces the draft andlowers the flame. When the thermostatic springs 93 and 1% cool, theywill contract, revolving the shaft 101 clockwise rotating the lever 102clockwise, raising the dampers D and D' against their weight toward openposition thus increasing the draft and consequently increas ing theflame.

When the knob 88 is preset by hand, it controls the general averagetemperature to be maintained in the following manner. Referring toFIGURE 5, the shaft 87 revolves the bevel gear 89 therewith. The bevelgear 89 revolves the bevel gear 117 rotating the universal shaft 118,bevel gear 119, vertical shaft 120 which is raised or lowered by meansof the threads 121 within the casing 68A of the float chamber 68. Thiscauses the lower end 122 of the rod 120 to engage the lever of the float70 holding the float valve 69 to a predetermined level of the float foropening, but will permit the said valve to close.

When hard fuels are to be burned, the gates 50 are closed by the levers56. This will operate the connecting rod 73 leading to the shut ofivalve 72, completely shutting oif the oil supply to the regulator unitR. The knob 88 is then manually turned counterclockwise rotating thedrum 90 counterclockwise until the offset por- 7 tion 2 of the flange 91makes a partial revolution and engages the roller 115 and the ball 111,which forces the plunger 113 to the position shown in FIGURE 12. Thismovement causes the spring loaded 'ball 123 to engage one of thedepressions 124 of the drum 99.

As the drum 90 is revolved counterclockwise, the lever 96 will leave itscontact with the stop 104 of the drum 99, there being no further need ofcontacting the said stop with the am. In order to set the damper forhard fuel, the knob 12.5 is then rotated clockwise. This will rotate thetubular shaft 8, including the drum 99 clockwise tightening thethermostatic spring 1W. Tension in spring 100 rotates the floating shaft181 clockwise, which will turn the crank 162 clockwise, raising theconnecting rod 103, together with the dampers D and D opening the sameto any desired position.

The spring loaded ball 123 will hold the drum 99 when the operator stopsrotating the knob 125. As the fire increases due to the heated draft,the thermostatic spring 1% will be heated and expand so that the shaftfill will rotate counterclockwise together with the crank M2, loweringthe dampers and tending to close them. In this manner, the dampers arefirst set for a desired tempera ture range and then are automaticallymoved toward closing when the flame and heat from the fire act on thethermostat unit to reduce the draft with resulting lowering of theflame. This in turn causes the thermostatic spring to contract movingthe dampers to increase the draft. The flame is thus regulated in arestricted temperature range.

Therefore, as is apparent from the above, when the fireplace is burningliquid fuel, thermostat T, by operation of knob 88, combines boththermostat elements for the purpose of closely controlling the operationof the dampers D and D. That is, by the use of the extra long bimetallicstrip, resulting from the combination of the two elements, thesensitivity of such elongated strip to variations in temperaturesoperates the dampers upon only a small change in temperature.

On the other hand, when solid fuel is being burned in the fireplace,such accurateness of damper control is not necessary or desirable. Bythe use of the single thermostat element 10%) damper control is lesssensitive and such dampers operate through a greater degree of rotation.

The principal draft of the present fireplace furnace is through thefront opening, although a side draft may if desired be provided throughintake 39. Air duct 11 is a cold air return from rooms heated by thefireplace through duct 9.

The air to be heated by the firebox F enters by way of the duct 11 andopening 10, passing along the bottom wall 4 of the shell S. This warmedair travels up both sides of the shell around the firebox through thespaces 30, and around each side of the smoke outlets O, as indicated bythe arrows in FIGURE 1. Warm air also moves between the smoke outletsthrough the channel 21 into the heat chamber 21A from where it moves byconvection current through the grill 34 into the room in which thefireplace is situated, reaching all parts of said room. Some of theheated air moves upwardly through duct 9 to heat rooms other than theone in which the fireplace is located. It can readily be seen that thewarmed air is efficiently heated by contact with large areas of theheated surface of the firebox.

By means of the present furnace, greater efliciency is achieved from afireplace so that it can by radiation and convection operate to serve asa furnace. The structure is open at the front so that the charm of afireplace is not lost and at the same time the arrangement is such thata forced draft is not necessary. It is of particular importance that theupper portion of the firebox is formed by the back wall 15, a top wall17 extending at substantially right angles thereto, and a partial frontwall 18. Wall 18 extends downwardly a distance suificient whereby thesmoke circulating spirally in the upper chamber of the firebox, asexplained hereinbefore, does not escape through the front opening of thefireplace. Impeding the smoke and the heated air velocity contributes ina great part to the invention in causing sulficient convection heatingfrom a fireplace to heat other rooms.

By reason of the wall '27 at the lower end of flue 8, the downdrafts arenot capable of blowing smoke into the room as such downdrafts arestopped or re-directed back up the flue.

Although a certain embodiment of the invention has been shown anddescribed, it is obvious that many modifications thereof are possible.The invention, therefore, is not to'be restricted except insofar as isnecessitated by the prior art and by the spirit of the appended claims.

What is claimed is:

1. In a fireplace, a single compartment, open-front firebox; a liquidfuel burner in said firebox which may be closed to permit the use of ahard fuel, said liquid fuel burner comprising an elongated chamber forholding and vaporizing the fuel, a pair of gates closing said chamberand movable to provide an elongated flame nozzle, means defining airinlets to said chamber, means defining a fuel inlet, an air inlet tubefor a pilot flame, and valve means on said fuel inlet means for closingthe fuel inlet means when said pilot flame is extinguished; a fuel lineleading to said fuel inlet; a fuel regulating unit incorporated in saidfuel line; a shut-off valve in said fuel regulating unit; and meansconnected between said liquid fuel burner and said shut-off valve forclosing said valve upon closing said burner.

2. In a fireplace, a single compartment, open-front firebox, a liquidfuel burner in said firebox, a pivoted grate supported over said liquidfuel burner for rotation between an open liquid fuel burning positionand a closed position for supporting hard fuel to be burned, a fuel lineleading to said liquid fuel burner, a fuel regulating unit incorporatedin said fuel line, a shut-off valve in said fuel regulating unit,connecting rod means connected between said pivoted grate and saidshut-oif valve for shutting off said valve upon rotation of said grateto a hard fuel burning position, a thermostat, setting means connectedto said thermostat for setting the latter, a pivotal damper connected tosaid thermostat and rotatable by the latter between open and closedpositions, said fuel regulating unit being provided with a float valveadjustable between open and closed positions, and means connectedbetween said setting means and said float valve to adjust said floatvalve between open and closed positions with the setting of said settingmeans as the latter sets said thermostats which control rotation of saiddampers in similar movements of opening and closing as the float valve.

3. A fireplace comprising means for burning fuel in fluid form, meansfor burning fuel in solid form, damper means in said fireplace, a dualcontrol thermostat unit having a pair of thermostatic elements, meansfor setting both of said thermostatic elements for operation together topreset said damper for movement which will achieve a desired temperaturerange when liquid fuel is burned, said pair of thermostatic elementswhen set as a unit providing a greater sensitivity in operation thanwhen set singly, and means for disengaging one of said thermostaticelements for operation singly of the other of said thermostatic elementsto preset said damper for movement which will achieve a desiredtemperature range when solid fuel is burned.

4. In a fireplace structure, a discharge passageway, a firebox having anexhaust port communicating with said discharge passageway, damper meanspivotally mounted in said discharge passageway for rotation between openand closed positions, a grate in said firebox movable between a closedposition for supporting solid fuel to be burned and an open position,liquid fuel burner means disposed below said grate for operation in theopen position of the latter, first thermostat means connected to said'damper means for controlling operation of the latter in the closedsolid fuel burning position of said grate, and second thermostat meansconnected to said damper means operative through said first thermostatmeans for controlling operation of said damper means in the open liquid.fuel burning position of said grate, said first and second thermostatmeans being operaitve to rotate said damper means toward closed positionas the temperature adjacent the fireplace increases and to rotate saiddamper means toward open position as the temperature adjacent thefireplace decreases.

5. In a fireplace structure, a discharge passageway, a grate movablebetween a closed position for supporting solid fuel to be burned and anopen position, liquid fuel burner means disposed below said grate foroperation in the open position of the latter, means defining an exhaustport communicating with said discharge passageway, pivoted dampers insaid discharge passageway, and thermostat means connected to saiddampers for controlling the operation of the latter, said thermostatmeans having dual operational functions rfor pivoting the dampersthrough different degrees of response for the two positions of thegrate.

References Cited in the file of this patent UNITED STATES PATENTS1,350,495 Hagenbuch Aug. 24, 1920 10 Johnson Feb. 17, 1925 De Florez May5, 1925 Cesa Oct. 18, 1927 Jacobs Feb. 21, 1928 Walters Aug. 21, 1928Claybaugh et al. Sept. 3, 1929 Lake July 8, 1930 Cage Mar. 1, 1938Larson Oct. 1, 1940 Donley May 27, 1941 Breese Apr. 18, 1944 Howrey Oct.31, 1950 Donley July 24, 1951 Snook Jan. 12, 1954 McCarty et a1 Oct. 4,1955 Dupler May 29, 1956 Johnson June 12, 1956 Carpenter June 25, 1957FOREIGN PATENTS Great Britain July 29, 1938 Canada Dec. 1, 1959

3. A FIREPLACE COMPRISING MEANS FOR BURNING FUEL IN FLUID FORM, MEANSFOR BURNING FUEL IN SOLID FORM, DAMPER MEANS IN SAID FIREPLACE, A DUALCONTROL THERMOSTAT UNIT HAVING A PAIR OF THERMOSTATIC ELEMENTS, MEANSFOR SETTING BOTH OF SAID THERMOSTATIC ELEMENTS FOR OPERATION TOGETHER TOPRESET SAID DAMPER FOR MOVEMENT WHICH WILL ACHIEVE A DESIRED TEMPERATURERANGE WHEN LIQUID FUEL IS BURNED, SAID PAIR OF THERMOSTATIC ELEMENTSWHEN SET AS A UNIT PROVIDING A GREATER SENSITIVITY IN OPERATION THANWHEN SET SINGLY, AND MEANS FOR DISENGAGING ONE OF SAID THERMOSTATICELEMENTS FOR OPERATION SINGLY OF THE OTHER OF SAID THERMOSTATIC ELEMENTSTO PRESET SAID DAMPER FOR MOVEMENT WHICH WILL ACHIEVE A DESIREDTEMPERATURE RANGE WHEN SOLID FUEL IS BURNED.